It's ridiculously easy. Replace just one drink—like a can of soda, a vanilla latte, or a glass of wine—with water each day and you could cut 50,000 calories a year. "That adds up to a 14-pound weight loss," says Biggest Loser nutritionist Rachel Beller, R.D., author of Eat to Lose, Eat to Win. The lesson: Drinks are treats too, so sip wisely.